Rheumatoid arthritis (RA) and chronic periodontitis (CP) may be related due to a bidirectional etiology. The evidence shows that CP could alter the clinical course of RA. We performed a systematic search to determine if CP alters the morbidity of RA, analyzing its clinical and molecular aspects. Of 552 initial articles found, 16 were selected for a thorough review. There is a greater prevalence of CP in patients with RA. Patients with RA have significantly higher values of periodontal clinical parameters than healthy controls. Arthritis activity is significantly greater in patients who suffer from CP and decreases with nonsurgical periodontal treatment. There is a significant relationship between the severity of CP and RA activity.